package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.dto.ScrollResult;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.Follow;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IFollowService;
import com.hmdp.service.IUserService;
import com.hmdp.utils.SystemConstants;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

import static com.hmdp.utils.RedisConstants.BLOG_LIKED_KEY;
import static com.hmdp.utils.RedisConstants.FEED_KEY;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {

    @Resource
    private IUserService userService;
    @Resource
    private IBlogService blogService;

    @Resource
    private BlogMapper blogMapper;

    @Resource
    private IFollowService followService;
    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Override
    public Result queryHotById(Integer current) {
        // 根据用户查询
        Page<Blog> page = blogService.query()
                .orderByDesc("liked")
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));
        // 获取当前页数据
        List<Blog> records = page.getRecords();
        // 查询用户
        records.forEach(blog ->{
            this.queryBlogUser(blog);
            this.isBlogLoked(blog);
        });
        return Result.ok(records);
    }

    /**
     * 查询top5的点赞用户
     * @param id
     * @return
     */
    @Override
    public Result queryBlogLikes(Long id) {
        // 1. 查询top5的用户数据
        String key=BLOG_LIKED_KEY+id;
        Set<String> top5 = stringRedisTemplate.opsForZSet().range(key, 0, 4);
        if(top5 == null || top5.isEmpty()){
            return Result.ok(Collections.emptyList());
        }

        // 2. 解析出其中的用户id
        List<Long> ids = top5.stream().map(Long::valueOf).collect(Collectors.toList());
        String idStr = StrUtil.join(",", ids);
        // 3.根据用户id查询用户 WHERE id IN ( 5 , 1 ) ORDER BY FIELD(id, 5, 1)
        List<UserDTO> userDTOS = userService.query()
                .in("id", ids).last("ORDER BY FIELD(id," + idStr + ")").list()
                .stream()
                .map(user -> BeanUtil.copyProperties(user, UserDTO.class))
                .collect(Collectors.toList());
        // 4.返回
        return Result.ok(userDTOS);
    }

    /**
     * 保存博文
     * @param blog
     * @return
     */
    @Override
    public Result saveBlog(Blog blog) {
        // 获取登录用户
        UserDTO user = UserHolder.getUser();
        blog.setUserId(user.getId());
        // 保存探店博文
        boolean isSuccess = save(blog);
        if(!isSuccess){
            return Result.fail("新增笔记失败！");
        }
        // 查询作者的所有粉丝 select * from tb_follow where follow_user_id = ？
        List<Follow> follows=blogMapper.queryFans(user.getId());
        // 进行推送
        for (Follow follow:follows) {
            // 获取粉丝的id
            Long userId = follow.getUserId();
            // 推送
            String key=FEED_KEY+userId;
            stringRedisTemplate.opsForZSet().add(key,blog.getId().toString(),System.currentTimeMillis());
        }
        // 返回id
        return Result.ok(blog.getId());
    }

    /**
     * 用户博客的分页查询
     * @param max
     * @param offset
     * @return
     */
    @Override
    public Result queryBlogOfFollow(Long max, Integer offset) { //Max表示上一次的最小标识，也就是当前的最大标识
        // 1. 获取当前用户，key查询收件箱
        Long userId = UserHolder.getUser().getId();

        // 2. 查询收件箱 ZREVRANGEBYSCORE key MAX MIN LIMIT offset count
        String key=FEED_KEY+userId;
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet()
                .reverseRangeByScoreWithScores(key, 0, max, offset, 2);

        // 非空判断
        if(typedTuples==null || typedTuples.isEmpty()){
            return Result.ok();
        }

        // 3. 解析数据：blogId,score，mintime(时间戳)，offset
        List<Long> ids = new ArrayList<>(typedTuples.size()); //指定好大小
        long minTime=Long.MAX_VALUE;
        int os= 1 ;
        for(ZSetOperations.TypedTuple<String> tuple:typedTuples){
            // 3.1 获取id
            String idStr = tuple.getValue();
            ids.add(Long.valueOf(idStr));
            // 3.2 获取分数(时间戳)
            long time= tuple.getScore().longValue();
            if(time==minTime){
                os++;
            }else{
                minTime = time;
                os = 1;
            }
        }

        os = minTime == max ? os : os + offset;
        // 4.根据id查询blog
        String idStr = StrUtil.join(",", ids);
        List<Blog> blogs = query().in("id", ids).last("ORDER BY FIELD(id," + idStr + ")").list();

        for (Blog blog : blogs) {
            // 4.1.查询blog有关的用户
            queryBlogUser(blog);
            // 4.2.查询blog是否被点赞
            isBlogLoked(blog);
        }

        // 5.封装并返回
        ScrollResult r = new ScrollResult();
        r.setList(blogs);
        r.setOffset(os);
        r.setMinTime(minTime);

        return Result.ok(r);
    }

    //这里如果你点了第一个，然后去点第二个它就会直接变成取消点赞，因为前面传入redis里面的value值是userId，所以应该改为id.toString()
    @Override
    public Result queryBlogById(Long id) {
        // 1.查询blog
        Blog blog = getById(id);
        if (blog == null) {
            return Result.fail("笔记不存在！");
        }
        // 2.查询blog有关的用户
        queryBlogUser(blog);
        // 3. 查询blog是否被点赞
        isBlogLoked(blog);
        return Result.ok(blog);
    }

    private void isBlogLoked(Blog blog) {
        UserDTO user = UserHolder.getUser();
        if(user == null){
            // 用户未登录
            return;
        }
        // 1.获取登录的用户
        Long userId = UserHolder.getUser().getId();
        // 2.判断当前的登录用户是否已经点赞
        String key=BLOG_LIKED_KEY+blog.getId();
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        blog.setIsLike(score!= null);

    }

    @Override
    public Result likeBlog(Long id) {
        // 1. 获取登录用户数据
        Long userid = UserHolder.getUser().getId();
        // 2. 判断当前的用户是否点赞
        String key = "blog:liked:"+id;
        Double score = stringRedisTemplate.opsForZSet().score(key, userid.toString());

        if(score==null) {
            // 3. 如果点赞了，可以点赞
            // 3.1 数据库点赞数+1
            boolean isSuccess = update().setSql("liked=liked+1").eq("id", id)
                    .update();
            // 3.2 保存用户到redis的set集合,zadd key value score
            if(isSuccess){
                stringRedisTemplate.opsForZSet().add(key,userid.toString(),System.currentTimeMillis());
            }

        }else {
            //4.如果已点赞，取消点赞
            //4.1 数据库点赞数-1
            boolean isSuccess = update().setSql("liked = liked - 1").eq("id", id).update();
            //4.2 把用户从Redis的set集合移除
            if(isSuccess){
                stringRedisTemplate.opsForZSet().remove(key,userid.toString());
            }
        }
        return Result.ok();
    }

    private void queryBlogUser(Blog blog){
        Long userId=blog.getUserId();
        User user = userService.getById(userId);
        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());

    }
}
